Each Assault Vehicle provides slightly different stats, so its best to use the one which gives the greatest Attacking stats

The Assault Vehicles are only present when the Commander is in the deployment, and can be seen above the marching rally or solo deployment within the game, the only drawback to this is it easily lets enemies see when your Commander is out of your base, potentially leaving you vulnerable to being attacked

The base boosts from the building itself make this an important building to level up